| 摘要 |
PURPOSE:To shorten greatly the executing time with respect to a divisor having a small number of effective digits by obtaining an accurate reciprocal number to said divisor and multiplying a divided by the divisor to obtain the quotient in case the divisor can be evolved to circulating decimals. CONSTITUTION:A deciding circuit 19 for propriety of evolution of circulating decimals decides that the evolution is possible for circulating decimals in case the evolution propriety information given from a table information storage unit 17 is approved and also the lower bits which are not used for retrieval of a table among those bits given from a normalizing circuit 14 are all set at zero. This result of decision is sent to a control circuit 11. Thus the circuit 11 discontinues the division and supplies the reciprocal numbers sent from an evolving circuit 18 for circulating decimals to a multiplier 21 via multiplier selection circuits 16 and 20 by an amount equal to the multiplier bits of the multiplier 21 that can be processed at a time. Then the dividends are sent to a dividend selecting circuit and a register 15 respectively. The reciprocal numbers are multiplied by said dividends through the multiplier 21, and a half carrier and a half sum are set to a half carrier register 22 and a half sum 24 to obtain the quotient at a multiplication result register 25. |
